Host status of weeds for Pratylenchus coffeae

Abstract

: Background: Populations of yam dry rot nematodes Scutellonema bradys , Pratylenchus coffeae and P. brachyurus can be sustained on weed hosts. Objective: Evaluate the reaction of 10 weeds frequently found in Alagoas to P. coffeae under greenhouse conditions. Methods: Two experiments were carried out in a completely randomized design, with 11 treatments, constituted of 10 weed species and the control ( Dioscorea cayenensis ) with eight replications. Plants were inoculated with 2,000 nematode specimens, nematode populations were evaluated in roots and soil 60 days after inoculation and the reproduction factor (RF) defined as RF = final population/initial population was calculated. Results: Euphorbia hyssopifolia showed RF=0 and was considered as non-host, whereas Chenopodium album, Amaranthus sp., Panicum maximum , Eleusine indica , Senna occidentalis , Emilia coccinea and Richardia brasiliensis , showed RF<1, being rated as poor hosts. Ricinus communis and Macroptilium lathyroides showed RF>1 only in the second trial and were classified as good hosts. Conclusion: Ricinus communis and M. lathyroides are potential sources of nematode inoculum for dry rot disease development.